EP0242688A1 - Surge arrester - Google Patents
Surge arrester Download PDFInfo
- Publication number
- EP0242688A1 EP0242688A1 EP87105067A EP87105067A EP0242688A1 EP 0242688 A1 EP0242688 A1 EP 0242688A1 EP 87105067 A EP87105067 A EP 87105067A EP 87105067 A EP87105067 A EP 87105067A EP 0242688 A1 EP0242688 A1 EP 0242688A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- electrode
- surge arrester
- arrester according
- gap
- activator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000012190 activator Substances 0.000 claims description 21
- 229910052751 metal Inorganic materials 0.000 claims description 16
- 239000002184 metal Substances 0.000 claims description 16
- 239000000919 ceramic Substances 0.000 claims description 12
- 229910052782 aluminium Inorganic materials 0.000 claims description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 7
- 239000011810 insulating material Substances 0.000 claims description 7
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 229910052709 silver Inorganic materials 0.000 claims description 4
- 238000005476 soldering Methods 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 4
- 238000009834 vaporization Methods 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 230000005496 eutectics Effects 0.000 claims description 3
- 229910002804 graphite Inorganic materials 0.000 claims description 3
- 239000010439 graphite Substances 0.000 claims description 3
- 238000009413 insulation Methods 0.000 claims description 3
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 230000008018 melting Effects 0.000 claims description 2
- 238000002844 melting Methods 0.000 claims description 2
- 239000004332 silver Substances 0.000 claims description 2
- 229910052710 silicon Inorganic materials 0.000 claims 1
- 229910052718 tin Inorganic materials 0.000 claims 1
- 238000009833 condensation Methods 0.000 description 7
- 230000005494 condensation Effects 0.000 description 7
- 239000007789 gas Substances 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- 239000010949 copper Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000007788 roughening Methods 0.000 description 2
- 229910000679 solder Inorganic materials 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 241000237942 Conidae Species 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T4/00—Overvoltage arresters using spark gaps
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T1/00—Details of spark gaps
- H01T1/24—Selection of materials for electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
- H01C7/12—Overvoltage protection resistors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T4/00—Overvoltage arresters using spark gaps
- H01T4/10—Overvoltage arresters using spark gaps having a single gap or a plurality of gaps in parallel
- H01T4/12—Overvoltage arresters using spark gaps having a single gap or a plurality of gaps in parallel hermetically sealed
Definitions
- the present invention relates to a surge arrester according to the preamble of claim 1.
- a surge arrester is known from US Pat. No. 3,702,952.
- the surge arrester described there contains a first electrode, which forms a cylindrical condensation gap with the ceramic housing, to which a circular disc-shaped and a cylindrical gap adjoin as a low-vaporization rear space.
- An ignition aid is produced there by sputtering electrode material onto the inner wall of the ceramic housing. It extends into the condensation gap.
- This type of ignition aid gives high static initial ignition values after long periods of dark storage.
- the effectiveness of the ignition aid deteriorates when current is passed, in particular during surge current loading, since metal of the electrodes evaporates and / or foreign gas outbursts increase the ignition voltage.
- the gaps that serve as low-vapor back spaces must be very narrow in the prior art, they should have a gap width of approximately 0.025 mm. This is necessary in the construction according to the prior art in order to prevent a short circuit due to metal precipitation along the surface of the ceramic housing, despite the very small gap lengths that can be achieved (in the example, a total length of approximately 1.1 mm). These very small gap widths require the highest precision of the individual parts and an extremely precise assembly. In practice, the ceramic has to be ground internally, which is complex and expensive.
- the object on which the present invention is based is to specify an embodiment of a surge arrester which can be produced rationally in accordance with the preamble of patent claim 1 while at the same time reducing the litter of the values obtained and in the reduction of the disturbing "light-dark effect", ie the sporadically occurring high static initial ignition values after a longer period between two discharges (after "dark storage").
- the end face of the second contact is advantageously covered with a metal serving as an activator.
- a metal serving as an activator As a result, the arc discharge can be concentrated on the discharge space between the parts of the electrodes coated with activator, or at least kept in the discharge gap.
- a high glow lamp voltage should be achieved for various applications.
- Activators with alkali and alkaline earth compounds of known composition are unsuitable for this, since they result in a too low glow burning voltage and / or gas contamination after the surge current exposure by after-gases or a chemical conversion of the activator and thus result in an instability of the characteristic values.
- Pure metals as activators are more stable under load, on the other hand they tend to atomize and, particularly in the case of multiple alternating current loads, result in considerable metal condensation on the housing parts visible from the discharge gap.
- metals can advantageously be used as activators, since a high degree of metal vapor condensation at non-critical points, e.g. the second electrode is reached and a sufficiently large receiving space for the metal vapor is available.
- the critical isolator sections are therefore hardly steamed, and the low-steam rear space is relatively easy to implement.
- An activator which is advantageous for a high glow burning voltage consists of a first component in the form of a melted layer of Al and a second component made of a metal which, together with the Al, forms a eutectic with a melting point which is below the soldering temperature.
- the substances Ag, Cu, Si Sn, Cr are particularly suitable as the second component if they are in metallic form.
- a silver layer is also suitable as an activator in a surge arrester according to the invention. It can be in powder form or by means of known coating methods, e.g. be galvanically applied.
- the metals added to the aluminum as a second component according to the invention prevent roughening of the electrode surface, which occurs during soldering and during operation if aluminum is used as an activator without these additives. This roughening changes the characteristic values considerably and can lead to a short circuit. According to our knowledge, it can be traced back to a spherical formation of the aluminum layer as a result of heating and can be Prevent additives.
- the aluminum advantageously also acts as a getter.
- a particularly powerful and space-saving embodiment is characterized by the features that the insulating material housing is made of ceramic and the electrodes consist essentially of copper, and that at least the second electrode is coated with a eutectic AgCu solder on the ceramic housing is soldered on, that in the area of the discharge gap an Ag-containing metal layer is applied as an activator layer on both electrodes, that the condensation gap has at least approximately the same width as the discharge gap, that the low-vapor deposition space is about 1.5 times as wide as the discharge gap, that the length of the condensation gap and the gap-shaped low-evaporation rear space is at least five times the corresponding gap width, that the end face of the cylinder wall of the first contact is rounded, that the distance of the end face of the cylinder wall from all parts of the second contact is approximately 1.5 times that The width of the discharge gap is.
- the dimensioning mentioned does not result in any discharges outside the discharge gap. It results in a very space-saving surge arrester. Ignition lines made of graphit
- the shortest path from the ignition aid along the ceramic housing to the first electrode is at least as long as the smallest mutual distance between the two electrodes in the region of the discharge gap.
- the proportion of the first component, aluminum is advantageously between about 10 and 40% by weight. This results in a firmly adhering layer without the formation of Al spheres.
- a simple to implement embodiment with little specimen scatter of the electrical characteristics contains the features that the inside diameter of the insulating material housing is about 1mm larger than the outside diameter of the first contact and that the inside diameter of the insulation material housing and the outer diameter of the first contact from their respective nominal value by no more than ⁇ 0.1mm.
- a surge arrester according to the invention is advantageously filled with a gas mixture of argon and hydrogen, the hydrogen content being between 5% and 20%.
- a first electrode 1, a cylindrical ceramic housing 3 and a second electrode 2 are hard-soldered to one another on the soldering surfaces 4 in a vacuum-tight manner.
- the first electrode 1 has a blind bore 12, which is composed of the cylindrical inner wall 19 and the bottom 13.
- the second electrode 2 has an end face 14 and a lateral surface 18.
- the gap 5 lies between the end face 14 and the bottom 13.
- the two electrodes 1 and 2 are preferably made of copper; but they can e.g. also consist of an alloy of the metals Fe, Ni, Co.
- the end face 11 of the cylinder wall 15 is rounded or chamfered.
- the distance from the end face 11 to any parts of the second electrode 2 is at least about 1.5 times the width of the smaller of the gaps 5 or 6.
- the low-vaporization rear space 7 lies between the cylinder wall 15 and the ceramic housing 3. Its length is approximately five times its width. At least one ignition line 10 is connected to the electrode 2 in an electrically conductive manner and extends into the low-vapor deposition space 7. Its end point is at least approximately the same distance from the first electrode 1 along the inner wall 16 of the ceramic housing 3 as the two electrodes 1 and 2 from one another in the columns 5 or 6.
- the one or more ignition lines 10 are preferably designed as graphite lines.
- a considerable reduction in the dimensions of the proposed surge arrester can be achieved by applying an activator layer 8, 9, 21, 22 to at least one boundary surface of the gaps 5 or 6.
- the discharge is held in the area of this activator layer, and the surge arrester can be reduced both in diameter and in axial extent, without discharges occurring at undesired locations which could reduce the lifespan of the surge arrester.
- both the inner wall 19 of the first electrode 1 and the outer surface 18 of the second electrode 2 and the bottom 13 of the first electrode 1 and the end face 14 of the second electrode 2 are covered with an activator layer 8, 9, 21, 22.
- columns 5 and 6 are fully used as discharge columns.
- the surge arrester can withstand a very high surge current load.
- FIG. 2 A particularly simple to produce embodiment is shown in Fig. 2, in which the end face 24 and the bottom 23 are each approximately conical and the angle of the cone shell to its axis of rotation corresponds to the angle of the cutting edge of a twist drill to its axis of rotation.
- the activator layers 29 and 30 are on the end face 24 and the Floor 23 provided.
- the gap 5 is narrower than the gap 6, the dimensions of the surge arrester in the axial direction can be kept relatively small.
- Fig. 3 shows an embodiment with a particularly long life.
- activator layers 8 and 9 are applied in the area of the gap 5, while there are no activator layers in the area of the gap 6.
- the gap 6 essentially acts as an additional condensation gap; the metal vapors that are produced do not for the most part reach the insulating material housing.
- the gap 6 is narrower than the gap 5.
- the second contact 2 in the vicinity of the end faces 11 has a region 28 with a reduced diameter, so that the distance between the end face 11 and the second contact 2 also meets the insulation requirements in this embodiment.
- the end faces 14 and the base 13 in this case have the shape of truncated cones which are delimited by circular surfaces 25 and 26 on the side with a smaller cross section.
- the circular surfaces 25 and 26 have different diameters, so that their edges 27 and 31 are offset from one another in the radial direction.
- the circular area 25 is smaller than the circular area 26. This prevents a current concentration along the edge 27.
- the gap 6 is narrower than the gap 5, so that the diameter of the surge arrester can be kept relatively small and the metal evaporating in the gap 5 is quickly precipitated in the relatively narrow gap 6.
- the area 17 on the ceramic insulator vapor-coated with metal is thereby kept particularly small. This embodiment thus ensures a particularly long service life of the surge arrester.
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- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Thermistors And Varistors (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
Ein Überspannungsableiter für eine hohe Stoßstromtragfähigkeit wird in seinen Kennwerten verbessert, indem eine erste Elektrode (1) eine Sackbohrung (12) aufweist, in die eine zweite Elektrode (2) hineinragt, wobei zwischen den beiden Elektroden (1 und 2) zumindest ein Entladungsspalt (5, 6) gebildet ist. Die Erfindung eignet sich für Überspannungsableiter mit hoher Lebensdauer und hoher Stoßstromtragfähigkeit.The characteristics of a surge arrester for high surge current carrying capacity are improved by a first electrode (1) having a blind bore (12) into which a second electrode (2) projects, with at least one discharge gap (2) between the two electrodes (1 and 2). 5, 6) is formed. The invention is suitable for surge arresters with a long service life and high surge current carrying capacity.
Description
Die vorliegende Erfindung betrifft einen Überspannungsableiter nach dem Oberbegriff des Patentanspruchs 1. Ein derartiger Überspannungsableiter ist aus der US-PS 3 702 952 bekannt. Der dort beschriebene Überspannungsableiter enthält eine erste Elektrode, die mit dem Keramikgehäuse einen zylinderförmigen Kondensationsspalt bildet, an den sich ein kreisscheibenförmiger und ein zylinderförmiger Spalt als bedampfungsarmer Hinterraum anschließen. Dort wird eine Zündhilfe durch Aufsputtern von Elektrodenmaterial auf die Innenwand des Keramikgehäuses hergestellt. Sie reicht in den Kondensationsspalt hinein. Diese Art der Zündhilfe gibt hohe statische Erstzündwerte nach längerer Dunkellagerung. Außerdem verschlechtert sich die Wirkung der Zündhilfe bei Stromdurchgang, insbesondere während der Stoßstrombelastung, da hierbei Metall der Elektroden abdampft und/oder Fremdgasausbrüche die Zündspannung heraufsetzen.The present invention relates to a surge arrester according to the preamble of claim 1. Such a surge arrester is known from US Pat. No. 3,702,952. The surge arrester described there contains a first electrode, which forms a cylindrical condensation gap with the ceramic housing, to which a circular disc-shaped and a cylindrical gap adjoin as a low-vaporization rear space. An ignition aid is produced there by sputtering electrode material onto the inner wall of the ceramic housing. It extends into the condensation gap. This type of ignition aid gives high static initial ignition values after long periods of dark storage. In addition, the effectiveness of the ignition aid deteriorates when current is passed, in particular during surge current loading, since metal of the electrodes evaporates and / or foreign gas outbursts increase the ignition voltage.
Die als bedampfungsarme Hinterräume dienenden Spalte müssen beim Stand der Technik sehr schmal sein, sie sollen eine Spaltbreite von ca. 0,025mm aufweisen. Dies ist bei der Konstruktion nach dem Stand der Technik erforderlich, um trotz der nur sehr kleinen realisierbaren Spaltlängen (im Beispiel ca. 1,1 mm Gesamtlänge) einen Kurzschluß infolge Metallniederschlages entlang der Oberfläche des Keramikgehäuses zu verhindern. Diese sehr geringen Spaltbreiten erfordern höchste Präzision der Einzelteile und einen äußerst präzisen Zusammenbau. In der Praxis muß die Keramik einen Innenschliff erhalten, welcher aufwendig und teuer ist.The gaps that serve as low-vapor back spaces must be very narrow in the prior art, they should have a gap width of approximately 0.025 mm. This is necessary in the construction according to the prior art in order to prevent a short circuit due to metal precipitation along the surface of the ceramic housing, despite the very small gap lengths that can be achieved (in the example, a total length of approximately 1.1 mm). These very small gap widths require the highest precision of the individual parts and an extremely precise assembly. In practice, the ceramic has to be ground internally, which is complex and expensive.
Die Aufgabe, die der vorliegenden Erfindung zugrunde liegt, besteht in der Angabe einer rationell zu fertigenden Ausführungsform eines Ableiters gemäß dem Oberbegriff vom Patentanspruch 1 bei gleichzeitiger Verringerung der Streu ung der erhaltenen Werte und in der Reduzierung des störenden "Hell-Dunkel-Effektes", d.h. der sporadisch auftretenden hohen statischen Erstzündwerte nach einem längeren Zeitraum zwischen zwei Entladungen (nach "Dunkellagerung").The object on which the present invention is based is to specify an embodiment of a surge arrester which can be produced rationally in accordance with the preamble of patent claim 1 while at the same time reducing the litter of the values obtained and in the reduction of the disturbing "light-dark effect", ie the sporadically occurring high static initial ignition values after a longer period between two discharges (after "dark storage").
Diese Aufgabe wird durch die kennzeichnenden Merkmale des Patentanspruches 1 gelöst. Durch das Zusammenwirken aller Merkmale des Patentanspruchs 1 wird erreicht, daß bei gleichen Außenabmessungen und zumindest gleichem Ableitvermögen sehr viel geringere Anforderungen an die mechanischen Toleranzen zur Gewährleistung einer verkleinerten Streubreite der elektrischen Daten ausreichen. Dabei wirken die Formgebung und die Art der Zündstriche für eine Lösung der gestellten Aufgabe zusammen, es ergibt sich eine vorteilhafte Ausführungsform, die in einfachen Justiervorrichtungen zusammengelötet werden kann.This object is achieved by the characterizing features of patent claim 1. The interaction of all the features of claim 1 ensures that, with the same external dimensions and at least the same dissipation capacity, much lower demands on the mechanical tolerances are sufficient to ensure a reduced spread of the electrical data. The shape and the type of the ignition lines work together for a solution to the task at hand, resulting in an advantageous embodiment which can be soldered together in simple adjustment devices.
Vorteilhaft ist die Stirnfläche des zweiten Kontaktes mit einem als Aktivator dienenden Metall bedeckt. Dadurch kann die Bogenentladung auf den Entladungsraum zwischen den mit Aktivator beschichteten Teilen der Elektroden konzentriert oder zumindest im Entladungsspalt gehalten werden.The end face of the second contact is advantageously covered with a metal serving as an activator. As a result, the arc discharge can be concentrated on the discharge space between the parts of the electrodes coated with activator, or at least kept in the discharge gap.
Für diverse Anwendungen soll eine hohe Glimmbrennspannung erreicht werden. Hierfür sind Aktivatoren mit Alkali- und Erdalkali-Verbindungen bekannter Zusammensetzung ungeeignet, da sie eine zu kleine Glimmbrennspannung ergeben und/oder eine Gasverunreinigung nach der Stoßstrombelastung durch Nachgasen oder eine chemische Umsetzung des Aktivators und damit eine Instabilität der Kennwerte ergeben. Reinmetalle als Aktivatoren sind belastungsstabiler, neigen dagegen zur Zerstäubung und ergeben insbesondere bei mehrfachen Wechselstrombelastungen eine beträchtliche Metallkondensation auf den aus dem Entladungsspalt sichtbaren Gehäuseteilen.A high glow lamp voltage should be achieved for various applications. Activators with alkali and alkaline earth compounds of known composition are unsuitable for this, since they result in a too low glow burning voltage and / or gas contamination after the surge current exposure by after-gases or a chemical conversion of the activator and thus result in an instability of the characteristic values. Pure metals as activators are more stable under load, on the other hand they tend to atomize and, particularly in the case of multiple alternating current loads, result in considerable metal condensation on the housing parts visible from the discharge gap.
In Verbindung mit der erfindungsgemäßen Gestaltung des Ableiters lassen sich Metalle als Aktivatoren vorteilhaft einsetzen, da ein hohes Maß an Metalldampfkondensation an unkritischen Stellen, z.B. der zweiten Elektrode erreicht wird und ein ausreichend großer Aufnahmeraum für den Metalldampf zur Verfügung steht. Die kritischen Isolatorstrecken werden daher kaum bedampft, der bedampfungsarme Hinterraum ist relativ leicht realisierbar. Ein für eine hohe Glimmbrennspannung vorteilhafter Aktivator besteht aus einer ersten Komponente in Form einer aufgeschmolzenen Schicht aus Al und einer zweiten Komponente aus einem Metall, welches mit dem Al ein Eutektikum mit einem Schmelzpunkt, welcher unter der Löttemperatur liegt, bildet. Als zweite Komponente eignen sich insbesondere die Stoffe Ag, Cu, Si Sn, Cr, wenn sie in metallischer Form vorliegen. Auch eine Silberschicht eignet sich als Aktivator in einem erfindungsgemäßen Überspannungsableiter. Sie kann in Pulverform oder mittels bekannter Beschichtungsverfahren, z.B. galvanisch aufgebracht sein.In connection with the design of the arrester according to the invention, metals can advantageously be used as activators, since a high degree of metal vapor condensation at non-critical points, e.g. the second electrode is reached and a sufficiently large receiving space for the metal vapor is available. The critical isolator sections are therefore hardly steamed, and the low-steam rear space is relatively easy to implement. An activator which is advantageous for a high glow burning voltage consists of a first component in the form of a melted layer of Al and a second component made of a metal which, together with the Al, forms a eutectic with a melting point which is below the soldering temperature. The substances Ag, Cu, Si Sn, Cr are particularly suitable as the second component if they are in metallic form. A silver layer is also suitable as an activator in a surge arrester according to the invention. It can be in powder form or by means of known coating methods, e.g. be galvanically applied.
Die erfindungsgemäß dem Aluminium als zweite Komponente zugesetzten Metalle verhindern eine Aufrauhung der Elektrodenoberfläche, die beim Einlöten und beim Betrieb entsteht, wenn Aluminium ohne diese Zusätze als Aktivator eingesetzt wird. Diese Aufrauhung verändert die Kennwerte erheblich und kann zum Kurzschluß führen. Sie ist gemäß unserer Erkenntnis auf eine Kugelbildung der Aluminiumschicht infolge Erhitzung zurückzuführen und läßt sich durch die o.g. Zusätze verhindern. Das Aluminium wirkt vorteilhafterweise gleichzeitig als Getter.The metals added to the aluminum as a second component according to the invention prevent roughening of the electrode surface, which occurs during soldering and during operation if aluminum is used as an activator without these additives. This roughening changes the characteristic values considerably and can lead to a short circuit. According to our knowledge, it can be traced back to a spherical formation of the aluminum layer as a result of heating and can be Prevent additives. The aluminum advantageously also acts as a getter.
Eine besonders leistungsstarke und dabei raumsparende Ausführungsform ist durch die Merkmale gekennzeichnet, daß das Isolierstoffgehäuse aus Keramik und die Elektroden im wesentlichen aus Kupfer bestehen, daß zumindest die zweite Elektrode mit einem eutektischen AgCu-Lot auf das Kermamik gehäuse aufgelötet ist, daß im Bereich des Entladungsspaltes auf beide Elektroden eine Ag-haltige Metallschicht als Aktivatorschicht aufgebracht ist, daß der Kondensationsspalt eine zumindest etwa gleiche Breite wie der Entladungsspalt aufweist, daß der bedampfungsarme Hinterraum etwa 1,5mal so breit ist wie der Entladungsspalt,daß die Länge des Kondensationsspaltes und des spaltförmigen bedampfungsarmen Hinterraumes mindestens das Fünffache der entsprechenden Spaltbreite beträgt, daß die Stirnseite der Zylinderwand des ersten Kontaktes abgerundet ist, daß der Abstand der Stirnseite der Zylinderwand von allen Teilen des zweiten Kontaktes etwa das 1,5-fache der Breite des Entladungsspaltes beträgt. Die genannte Bemessung ergibt im Zusammenhang mit dem genannten Aktivator und genanntem Lot keine Entladungen außerhalb des Entladungsspaltes. Sie ergibt einen sehr platzsparenden Überspannungsableiter. Dabei sind Zündstriche aus Graphit für eine gleichmäßige Zündspannung vorteilhaft.A particularly powerful and space-saving embodiment is characterized by the features that the insulating material housing is made of ceramic and the electrodes consist essentially of copper, and that at least the second electrode is coated with a eutectic AgCu solder on the ceramic housing is soldered on, that in the area of the discharge gap an Ag-containing metal layer is applied as an activator layer on both electrodes, that the condensation gap has at least approximately the same width as the discharge gap, that the low-vapor deposition space is about 1.5 times as wide as the discharge gap, that the length of the condensation gap and the gap-shaped low-evaporation rear space is at least five times the corresponding gap width, that the end face of the cylinder wall of the first contact is rounded, that the distance of the end face of the cylinder wall from all parts of the second contact is approximately 1.5 times that The width of the discharge gap is. In connection with the activator and the solder mentioned, the dimensioning mentioned does not result in any discharges outside the discharge gap. It results in a very space-saving surge arrester. Ignition lines made of graphite are advantageous for a uniform ignition voltage.
Für die Einhaltung der dynamischen Zündspannung reicht es aus, wenn der kürzeste Weg von der Zündhilfe entlang dem Keramikgehäuse zur ersten Elektrode (die Restisolationsstrecke) zumindest ebenso groß ist wie der kleinste gegenseitige Abstand der beiden Elektroden im Bereich des Entladungsspaltes.To maintain the dynamic ignition voltage, it is sufficient if the shortest path from the ignition aid along the ceramic housing to the first electrode (the residual insulation path) is at least as long as the smallest mutual distance between the two electrodes in the region of the discharge gap.
Der Anteil der ersten Komponente, des Aluminiums, liegt vorteilhaft zwischen etwa 10 und 40 Gew%. Dadurch ergibt sich eine festhaftende Schicht ohne Bildung von Al-Kügelchen.The proportion of the first component, aluminum, is advantageously between about 10 and 40% by weight. This results in a firmly adhering layer without the formation of Al spheres.
Ein einfach realisierbare Ausführungsform mit geringer Exemplarstreuung der elektrischen Kennwerte enthält die Merkmale, daß der Innendurchmesser des Isolierstoffgehäuses um ca. 1mm größer ist als der Außendurchmesser des ersten Kontaktes und daß der Innendurchmesser des Isolier stoffgehäuses und der Außendurchmesser des ersten Kontaktes von ihrem jeweiligen Nennwert um nicht mehr als ±0,1mm abweichen.A simple to implement embodiment with little specimen scatter of the electrical characteristics contains the features that the inside diameter of the insulating material housing is about 1mm larger than the outside diameter of the first contact and that the inside diameter of the insulation material housing and the outer diameter of the first contact from their respective nominal value by no more than ± 0.1mm.
Ein erfindungsgemäßer Überspannungsableiter ist vorteilhaft mit einem Gasgemisch aus Argon und Wasserstoff gefüllt, wobei der Wasserstoffanteil zwischen 5% und 20% liegt.A surge arrester according to the invention is advantageously filled with a gas mixture of argon and hydrogen, the hydrogen content being between 5% and 20%.
Die Erfindung wird nun anhand von drei Figuren näher erläutert. Sie ist nicht auf die in den Figuren gezeigten Beispiele beschränkt. Die Figuren zeigen erfindungsgemäße Überspannungsableiter in geschnittener Ansicht.The invention will now be explained with reference to three figures. It is not limited to the examples shown in the figures. The figures show surge arresters according to the invention in a sectional view.
Eine erste Elektrode 1, ein zylinderförmiges Keramikgehäuse 3 und eine zweite Elektrode 2 sind miteinander an den Lötflächen 4 vakuumdicht hartverlötet. Die erste Elektrode 1 weist eine Sackbohrung 12 auf, die sich aus der zylindrischen Innenwand 19 und dem Boden 13 zusammensetzt. Die zweite Elektrode 2 weist eine Stirnfläche 14 und eine Mantelfläche 18 auf.A first electrode 1, a cylindrical
Zwischen der Stirnfläche 14 und dem Boden 13 liegt der Spalt 5. An diesem Spalt 5 schließt sich zwischen der Innenwand 19 der ersten Elektrode 1 und der Mantelfläche 18 der zweiten Elektrode 2 ein Spalt 6 an, der zumindest dieselbe Breite aufweist wie der Spalt 5. Die beiden Elektroden 1 und 2 sind vorzugsweise aus Kupfer; sie können aber z.B. auch aus einer Legierung der Metalle Fe, Ni, Co bestehen.The
Die Stirnfläche 11 der Zylinderwand 15 ist abgerundet oder angefast. Der Abstand von der Stirnfläche 11 zu beliebigen Teilen der zweiten Elektrode 2 beträgt zumindest etwa das 1,5-fache der Breite des kleineren der Spalte 5 oder 6.The
Zwischen der Zylinderwand 15 und dem Keramikgehäuse 3 liegt der bedampfungsarme Hinterraum 7. Seine Länge beträgt etwa das Fünffache seiner Breite. Mindestens ein Zündstrich 10 ist mit der Elektrode 2 elektrisch leitend verbunden und reicht in den bedampfungsarmen Hinterraum 7 hinein. Sein Endpunkt besitzt zur ersten Elektrode 1 entlang der Innenwand 16 des Keramikgehäuses 3 zumindest etwa denselben Abstand, wie die beiden Elektroden 1 und 2 voneinander in den Spalten 5 oder 6. Der oder die Zündstriche 10 sind vorzugsweise als Graphitstriche ausgebildet.The low-vaporization
Eine erhebliche Verkleinerung der Abmessungen des vorgeschlagenen Überspannungsableiters ist erreichbar, indem auf zumindest eine Begrenzungsfläche der Spalte 5 oder 6 eine Aktivatorschicht 8, 9, 21, 22 aufgebracht ist. Dadurch wird die Entladung im Bereich dieser Aktivatorschicht gehalten, der Überspannungsableiter kann sowohl im Durchmesser als auch in der axialen Ausdehnung verkleinert werden, ohne daß Entladungen an unerwünschten Stellen auftreten, welche die Lebensdauer des Überspannungsableiters herabsetzen könnten.A considerable reduction in the dimensions of the proposed surge arrester can be achieved by applying an
In Fig. 1 sind sowohl die Innenwand 19 der ersten Elektrode 1 und die Mantelfläche 18 der zweiten Elektrode 2 als auch der Boden 13 der ersten Elektrode 1 und die Stirnfläche 14 der zweiten Elektrode 2 mit einer Aktivatorschicht 8, 9, 21, 22 bedeckt. Dadurch werden die Spalte 5 und 6 vollständig als Entladungsspalte ausgenutzt. Der Überspannungsableiter kann eine sehr hohe Stoßstrombelastung vertragen.In Fig. 1, both the
Eine besonders einfach herzustellende Ausführungsform ist in Fig. 2 dargestellt, bei der die Stirnfläche 24 und der Boden 23 jeweils annähernd kegelförmig ausgebildet sind und der Winkel des Kegelmantels zu seiner Rotationsachse dem Winkel der Schneide eines Spiralbohrers zu dessen Rotationsachse entspricht. In diesem Beispiel sind nur die Aktivatorschichten 29 und 30 auf der Stirnfläche 24 und dem Boden 23 vorgesehen. Der Spalt 5 ist schmaler als der Spalt 6, die Abmessungen des Überspannungsableiters in axialer Richtung kann relativ klein gehalten werden.A particularly simple to produce embodiment is shown in Fig. 2, in which the
Fig. 3 zeigt eine Ausführungsform mit einer besonders langen Lebensdauer. Auch hier sind Aktivatorschichten 8 und 9 im Bereich des Spaltes 5 angebracht, während im Bereich des Spaltes 6 keine Aktivatorschichten vorhanden sind. Dadurch wirkt der Spalt 6 im wesentlichen als zusätzlicher Kondensationsspalt, die entstehenden Metalldämpfe gelangen zum größten Teil nicht an das Isolierstoffgehäuse. Der Spalt 6 ist schmaler als der Spalt 5. Um garantiert Fehlzündungen im Bereich der Stirnflächen 11 zu vermeiden, weist der zweite Kontakt 2 in der Nachbarschaft der Stirnflächen 11 einen Bereich 28 mit verringertem Durchmesser auf, so daß der Abstand zwischen der Stirnfläche 11 und dem zweiten Kontakt 2 auch bei dieser Ausführungsform den Isolationsanforderungen genügt.Fig. 3 shows an embodiment with a particularly long life. Here, too,
Die Stirnflächen 14 und der Boden 13 weisen in diesem Fall die Form von Kegelstümpfen auf, die auf der Seite mit kleinerem Querschnitt durch Kreisflächen 25 bzw. 26 begrenzt sind. Die Kreisflächen 25 und 26 weisen unterschiedliche Durchmesser auf, so daß ihre Kanten 27 und 31 in radialer Richtung gegeneinander versetzt liegen. Die Kreisfläche 25 ist dabei kleiner als die Kreisfläche 26. Dadurch wird eine Stromkonzentration entlang der Kante 27 vermieden. In dieser Ausführungsform ist der Spalt 6 schmaler als der Spalt 5, so daß der Durchmesser des Überspannungsableiters relativ klein gehalten werden kann und im relativ engen Spalt 6 das im Spalt 5 abdampfende Metall sich schnell niederschlägt. Der mit Metall bedampfte Bereich 17 auf dem Keramikisolator wird dadurch besonders klein gehalten. Diese Ausführungsform gewährleistet also eine besonders lange Lebensdauer des Überspannungsableiters.The end faces 14 and the base 13 in this case have the shape of truncated cones which are delimited by circular surfaces 25 and 26 on the side with a smaller cross section. The circular surfaces 25 and 26 have different diameters, so that their edges 27 and 31 are offset from one another in the radial direction. The circular area 25 is smaller than the circular area 26. This prevents a current concentration along the edge 27. In this embodiment, the
Claims (10)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE3613599 | 1986-04-22 | ||
DE3613599 | 1986-04-22 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0242688A1 true EP0242688A1 (en) | 1987-10-28 |
EP0242688B1 EP0242688B1 (en) | 1990-07-18 |
Family
ID=6299259
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP87105067A Expired - Lifetime EP0242688B1 (en) | 1986-04-22 | 1987-04-06 | Surge arrester |
Country Status (5)
Country | Link |
---|---|
US (1) | US4739439A (en) |
EP (1) | EP0242688B1 (en) |
JP (1) | JPS62256394A (en) |
KR (1) | KR950009084B1 (en) |
DE (1) | DE3763733D1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19632417C1 (en) * | 1996-08-05 | 1998-05-07 | Siemens Ag | Hydrogen-containing gas-filled surge diverter |
WO2013152948A1 (en) * | 2012-04-12 | 2013-10-17 | Epcos Ag | Over-voltage arrester |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
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EP0378963B1 (en) * | 1989-01-18 | 1994-06-22 | Siemens Aktiengesellschaft | Spark gap element for shielded mounting |
US4907118A (en) * | 1989-03-09 | 1990-03-06 | Curtis Manufacturing Company, Inc. | Visual indicator electrical plug-type surge protector and systems |
ES2076204T3 (en) * | 1989-11-02 | 1995-11-01 | Siemens Ag | DISTANCE FROM THE ACTIVABLE CONNECTION SPARK. |
JPH03101892U (en) * | 1990-02-06 | 1991-10-23 | ||
JP2725763B2 (en) * | 1994-06-30 | 1998-03-11 | 矢崎総業株式会社 | Discharge tube and ignition device with series gap |
DE102005016848A1 (en) * | 2005-04-12 | 2006-10-19 | Epcos Ag | Surge arresters |
DE102005036265A1 (en) * | 2005-08-02 | 2007-02-08 | Epcos Ag | radio link |
JP2009508320A (en) * | 2005-09-14 | 2009-02-26 | リッテルフューズ,インコーポレイティド | Surge arrester with gas, activation compound, ignition stripe and method thereof |
JP4930053B2 (en) * | 2006-03-29 | 2012-05-09 | 三菱マテリアル株式会社 | surge absorber |
KR101311686B1 (en) * | 2006-03-29 | 2013-09-25 | 미츠비시 마테리알 가부시키가이샤 | Surge absorber |
JP4770550B2 (en) * | 2006-03-29 | 2011-09-14 | 三菱マテリアル株式会社 | surge absorber |
JP4872645B2 (en) * | 2006-12-14 | 2012-02-08 | 三菱マテリアル株式会社 | surge absorber |
WO2012105014A1 (en) * | 2011-02-02 | 2012-08-09 | 株式会社コンド電機 | Electric discharge element and method for manufacturing same |
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DE2934237C2 (en) * | 1979-08-24 | 1983-02-17 | Aeg-Telefunken Ag, 1000 Berlin Und 6000 Frankfurt | Surge arresters |
DE3118137C2 (en) * | 1981-05-07 | 1986-04-24 | Siemens AG, 1000 Berlin und 8000 München | Gas discharge surge arrester with air spark gap connected in parallel |
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1987
- 1987-04-06 EP EP87105067A patent/EP0242688B1/en not_active Expired - Lifetime
- 1987-04-06 DE DE8787105067T patent/DE3763733D1/en not_active Expired - Fee Related
- 1987-04-15 US US07/038,662 patent/US4739439A/en not_active Expired - Fee Related
- 1987-04-17 JP JP62096116A patent/JPS62256394A/en active Pending
- 1987-04-22 KR KR1019870003842A patent/KR950009084B1/en not_active IP Right Cessation
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GB544264A (en) * | 1941-01-13 | 1942-04-03 | Lodge Plugs Ltd | Improvements relating to electric spark gaps |
US3702952A (en) * | 1971-10-12 | 1972-11-14 | Western Electric Co | Gas tube surge protective device and method for making the device |
DE3207663A1 (en) * | 1982-03-03 | 1983-09-08 | Siemens AG, 1000 Berlin und 8000 München | SURGE PROTECTOR WITH A GAS-FILLED HOUSING |
US4491893A (en) * | 1982-05-25 | 1985-01-01 | Reliance Electric Company | Gas filled surge arrester |
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DE19632417C1 (en) * | 1996-08-05 | 1998-05-07 | Siemens Ag | Hydrogen-containing gas-filled surge diverter |
WO2013152948A1 (en) * | 2012-04-12 | 2013-10-17 | Epcos Ag | Over-voltage arrester |
US9614370B2 (en) | 2012-04-12 | 2017-04-04 | Epcos Ag | Surge arrester |
Also Published As
Publication number | Publication date |
---|---|
DE3763733D1 (en) | 1990-08-23 |
KR870010658A (en) | 1987-11-30 |
EP0242688B1 (en) | 1990-07-18 |
KR950009084B1 (en) | 1995-08-14 |
US4739439A (en) | 1988-04-19 |
JPS62256394A (en) | 1987-11-09 |
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